The relation between cell structure, nucleic acid metabolism and protein synthesis are being investigated. A cytoskeletal structure has been prepared from HeLa cells which retains many morphological aspects of the intact cell and which has all active polyribosomes attached. The coupling between polyribosomes and the cytoskeleton is shown to be through the mRNA moiety. The results suggest a topological localization of protein synthesis which is being investigated. HnRNA transcripts are found associated with the nuclear skeleton and not with chromatin. Processing appears to take place on skeletal structures. The small RNA species C and D appear to be structural components of hnRNP particles and may play a role in the regulation of processing of hnRNA. Poly(A) -mRNA appears related to some structure and has been found to code for one of the three cellular actin molecules and two of the major nuclear skeleton components. BIBLIOGRAPHIC REFERENCES: Herman, R., Williams, J. and Penman, S. (1976). Message and Non-Message Sequences Adjacent to Poly(A) in Steady-State Heterogeneous Nuclear RNA of HeLa Cells. Cell, 7: 429-437. Johnson, L.F., Penman, S. and Green, H. (1976). Increasing Content of Poly(A) plus mRNA of Serum-stimulated Cells in the Absence of Ribosome Synthesis. J. Cell. Physiology, 87: 141-146.